JP2001080948A - Moisture absorbing/desorbing gypsum board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high quality gypsum board excellent in moisture absorbing/desorbing efficiency and water-repellence, good in dimensional stability when moisture is absorbed while excellent properties, convenience and economical efficiency are provided similarly to the conventional gypsum board by blending gypsum core with a water-repellence imparting agent and an inorganic moisture absorbing/desorbing material. SOLUTION: As the silicone-based water-repellence imparting agent, organosiloxane and organopolysiloxane are exemplified and, as the paraffin- based water-repellence imparting agent, such an emulsion can be used, as is obtained by incorporating polyvinyl alcohol in the emulsion of waxes having 40-90 deg.C melting point and a derivative of an olefin-maleic anhydride polymer. The amount of the water-repellence imparting agent to be added is 0.05-1 pts.wt. when the silicone-based water-repellence imparting agent is used and 0.5-5 pts.wt. when the paraffin-based water-repellence imparting agent is used respectively based on 100 pts.wt. gypsum. As the inorganic moisture absorbing/desorbing material, for example, zeolite group, diatomaceous earth, silicic shale, or the like, can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gypsum board excellent in moisture absorption / desorption performance, and more particularly, to an excellent moisture absorption / desorption property.
The present invention relates to a gypsum board which has both water repellency and dimensional stability and is suitable as an interior construction material for walls and ceilings of houses.

[0002]

2. Description of the Related Art In the recent construction industry, it is necessary to provide inexpensive and high-quality products while taking into consideration the effective use of resources. For example, in the housing industry,
While cost reductions are being promoted through rationalization and efficiency of construction methods, building materials are being improved in performance and quality are being stabilized, and from the viewpoint of energy saving, the design and design are designed to enhance the heat insulation performance and airtightness of indoor spaces. It is increasingly being constructed. Increasing the heat insulation and airtightness of the interior space may easily cause dew condensation and impair the livability, but in recent years there has been a remarkable increase in occupants' interest in health and comfortable living spaces. Needless to say, there is a strong demand for the development of building materials having excellent moisture absorption / desorption performance that is effective for indoor humidity control.

[0003] On the other hand, as a commercially available moisture absorbing and releasing material for interior, a panel formed by compression molding a substance having excellent moisture absorbing and releasing properties,
There are known wet finishing materials containing these substances, cloth cloths containing activated carbon as a moisture absorbing / releasing substance, and the like.
However, these materials are not only expensive but also complicated in construction, so that the construction cost is extremely high and the economy is poor. Furthermore,
Similar to wood, these moisture-absorbing and desorbing panels, etc., undergo dimensional changes during moisture absorption and desorption, especially when absorbing water, and as a result, materials such as warpage and cracks are generated during and after construction. "Rack", that is, a problem of a decrease in dimensional stability.

[0004]

On the other hand, materials for interior construction such as walls and ceilings of houses which are the foundations of these interior materials and the like include fire and fire resistance, sound insulation, heat insulation, workability and the like. Gypsum board is frequently used because it is inexpensive in addition to excellent performance. Therefore, if it is possible to improve the quality of the gypsum board without deteriorating the performance and economics of the gypsum board, prevent dew condensation, and produce a product excellent in moisture absorption and desorption performance that is effective also for indoor humidity control, the above-mentioned industrial industry will be developed. It can be a powerful tool for responding to the needs of the world.

[0005] Gypsum board is originally a material having a certain degree of moisture absorption and desorption properties and good dimensional stability, but it is necessary to add moisture absorption and desorption properties to the gypsum board at the time of moisture absorption and desorption, especially at the time of water absorption. Dimensional change may be promoted. In addition, gypsum board has another problem that its strength is impaired if it is held in an excessively water-absorbed state, especially in a humid place.
A gypsum board with improved water repellency is used to suppress the absorption of water by the gypsum core of the gypsum board. Such materials have slightly lower moisture absorption / release performance than conventional materials, and cannot meet the above-mentioned demands of the industry.

Accordingly, an object of the present invention is to provide a gypsum board having more excellent moisture absorption / desorption performance while maintaining the excellent performance, convenience, and excellent economic efficiency of a gypsum board. An object of the present invention is to provide a high quality gypsum board which has excellent water repellency and good dimensional stability during water absorption.

[0007]

The above object is achieved by the present invention described below. That is, the present invention is a gypsum board, wherein a gypsum core is mixed with a water repellency-imparting agent and an inorganic hygroscopic substance.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to embodiments of the present invention. The present inventors have conducted intensive studies to solve the above-described problems of the prior art, and as a result of including an inorganic hygroscopic substance in the gypsum core and using a water repellent in combination with the gypsum core, to prevent dew condensation and Gypsum that is effective for indoor humidity control, has excellent moisture absorption and desorption performance, and is also excellent in water repellency and dimensional stability, effectively preventing various problems caused by material "roughness" at the time of water absorption The inventors have found that a board can be easily obtained, and have reached the present invention. That is,
According to the study of the present inventors, by adding an inorganic moisture-absorbing / desorbing substance to a gypsum core as described later, it is possible to impart further moisture-absorbing / desorbing performance to a gypsum board. If it is used alone, it causes a decrease in dimensional stability at the time of water absorption, causing problems such as warpage and cracking due to "roughness" of the material. This proved that such a problem could be solved effectively.

Further, the present inventors have conducted the following detailed investigation on the relationship between the inorganic moisture-absorbing / desorbing substance and the water repellency-imparting agent used in combination, and as a result, the following has been found. Specifically, the amount of the water repellency imparting agent to be added to the gypsum core, the total water absorption of the gypsum core for 2 hours (based on JIS A6901), and the elongation of the gypsum core at the time of 2 hours of total water absorption are measured. A study was conducted. As a result, first, in order to effectively prevent the occurrence of warpage and cracks due to “roughness” of the gypsum board at the time of moisture absorption and desorption, particularly at the time of water absorption, the measured value of the elongation rate of the gypsum core at the time of total absorption of water for 2 hours is 0%. It was found that it was necessary to configure the gypsum board so as to be 0.1% or less. Furthermore, by blending the water repellency imparting agent into the gypsum core,
More preferably, it has been found that by adding a predetermined amount of a water repellency-imparting agent, not only the water repellency of the gypsum core can be improved, but also the value of the elongation can be significantly reduced. From the above, in the gypsum core, by blending a water repellency-imparting agent together with an inorganic moisture-absorbing and desorbing substance, high moisture-absorbing and desorbing properties and water repellency can be obtained. I was convinced that the dimensional stability of the board could be secured.

Next, each material used in the gypsum board of the present invention will be described. First, the water repellency-imparting agent constituting the gypsum board of the present invention will be described. As described above, such a water repellency-imparting agent is used by being compounded in gypsum, which is a main raw material of a gypsum core. For example, a cement-based composition or a known gypsum-based composition used for a gypsum-based composition Any of various water repellency-imparting agents can be used.
The present inventors, these water repellency imparting agent, performance,
Various examinations were conducted in consideration of price, curing time, etc. As a result, in the gypsum board of the present invention, it was found that the following silicone-based water repellency-imparting agents or paraffin-based water-repellency-imparting agents were suitable.

As the silicone-based water repellency-imparting agent, any known one can be used, and specifically, for example, as described in Japanese Patent No. 2739872, Organosiloxanes having a hydrogen atom bonded to an atom, Patent 268679
An organopolysiloxane as described in JP-A No. 2 can be mentioned.

Preferable examples of paraffin-based water repellents include waxes having a melting point of 40 to 90 ° C. and olefin-maleic anhydride derivatives described in JP-B-7-61889. Below, an emulsion obtained by emulsifying in water and containing polyvinyl alcohol can be used. Such an emulsion has been developed to impart water repellency to gypsum and to provide a water repellent gypsum composition with excellent performance. For example, "Diaproof" manufactured by Mitsubishi Chemical Corporation
It is commercially available as (trade name).

The amount of the water repellency-imparting agent to be added to the gypsum core constituting the gypsum board of the present invention is not particularly limited, but if it is a silicone-based water repellency-imparting agent, it is based on 100 parts by weight of gypsum. 0.05 to 1 part by weight, preferably 0.3 to 0.7 part by weight, and 0.5 to 5 parts by weight per 100 parts by weight of gypsum if it is a paraffin-based water repellent.
Preferably, the content is 2 to 4 parts by weight. That is, when the amount of these water repellency imparting agents to be added to the gypsum core is increased within the above range, the above-mentioned total water absorption of 2 hours and 2
The elongation rate of the gypsum core at the time of total water absorption can be reduced, and the water repellency and dimensional stability are improved. However, even if it is blended in a state exceeding the above range, the cost of the material is increased instead of the effect. Is expensive and economical. On the other hand, in any of the water repellency-imparting agents, if the amount is less than the above range, the amount is too small, and it is difficult to obtain a gypsum board having desired water repellency and dimensional stability.

Next, an inorganic moisture-absorbing / desorbing substance to be added to the gypsum core constituting the gypsum board of the present invention will be described. The inorganic moisture-absorbing and desorbing substance that can be used for the gypsum board of the present invention is not particularly limited, and any substance that exhibits moisture-absorbing and desorbing properties depending on the surrounding humidity where the gypsum board is placed can be used. As inorganic hygroscopic substances, for example, zeolite group, diatomaceous earth (for example, Wakkanai diatom shale etc.), siliceous shale, halloysite, clay minerals such as montmorillonite (acid clay) are generally known,
In the present invention, any of these can be used. In particular, those treated with acid or those treated with calcination,
It is known to exhibit better moisture absorption / release properties than untreated products, and is particularly suitable. For example, activated clay obtained by treating acid clay with acid can be suitably used. According to the study of the present inventors, by mixing one or more of the above-mentioned inorganic moisture-absorbing and desorbing substances into the constituent material of the gypsum core, the moisture absorption and desorption of the gypsum board originally has It was found that the performance could be further improved.

The amount of the inorganic hygroscopic substance to be mixed in the gypsum core is 3 to 100 parts by weight of gypsum.
To 30 parts by weight, preferably 5 to 20 parts by weight. These inorganic moisture-absorbing and desorbing substances can increase the moisture-absorbing and desorbing performance as the blending amount increases, but, on the other hand, when the amount is too large, the strength of the gypsum board is decreased, which is not preferable. . On the other hand, if the amount is less than 3 parts by weight, the amount is too small, and no clear improvement in moisture absorption / desorption performance can be achieved.

In the gypsum board of the present invention, as described above, by adding a water repellency-imparting agent to the gypsum core in addition to these inorganic moisture-absorbing and desorbing substances, it is preferable that the inorganic absorbent By blending the wet substance and the water repellency-imparting agent in the respective predetermined amounts, the performances of both are offset or the adverse effects of blending both do not occur. It becomes possible to add synergistically in the state. As a result, it is possible to improve the moisture absorption and release properties of the gypsum board,
Water repellency and dimensional stability at the time of water absorption were exhibited, and a gypsum board having excellent performance was obtained.

Incidentally, the gypsum board of the present invention can be manufactured in a normal gypsum board production line, and other compounding materials include, for example, a known β-type hemihydrate gypsum and α
It goes without saying that a known admixture such as pulp fiber and / or glass fiber, a known foaming agent, a setting regulator and the like can be used for the type hemihydrate gypsum or a mixture thereof.

[0018]

Next, the present invention will be described more specifically with reference to examples and comparative examples. Examples 1 to 60 As a water repellency imparting agent blended in the gypsum boards of Examples and Comparative Examples, a silicone water repellency imparting agent and a paraffin water repellency imparting agent were used, respectively. Specifically, "KF-9" manufactured by Shin-Etsu Chemical Co., Ltd. is used as a silicone-based water repellent.
9 "(trade name) and" Diaproof "(trade name) manufactured by Mitsubishi Chemical Corporation as a paraffin-based water repellency imparting agent. Activated clay and zeolite were used as the inorganic hygroscopic substance. Specifically, "Nikkalite G-36" manufactured by Japan Activated Shirato Co., Ltd. as activated clay,
Zeolite's "Shirato SGW"
-B "(trade name).

The amount of "KF-99" to be blended with the gypsum core in a normal gypsum board production line using these blended materials is in the range of 0.1 to 1.0 part by weight per 100 parts by weight of gypsum. And the amount of “Nicalite G-36” to be mixed with the gypsum core is 5 to 2 parts per 100 parts by weight of gypsum.
Example 1 of the composition shown in Table 1 while changing within the range of 0 parts by weight
~ 15 types of gypsum boards were obtained. Further, the amount of “Diaproof” to be blended into the gypsum core is changed in the range of 0.5 to 4 parts by weight with respect to 100 parts by weight of gypsum, and the amount of “Nikkalite G-36” to be blended into the gypsum core And plaster 1
Change in the range of 5 to 20 parts by weight with respect to 00 parts by weight,
15 types of gypsum boards of Examples 16 to 30 having the composition shown in Table 2 were obtained. Next, the amount of “KF-99” was changed within the above range, and “Shirasu SGW-B” to be mixed with the gypsum core
Was changed in the range of 5 to 20 parts by weight with respect to 100 parts by weight of gypsum, and 1 of Examples 31 to 45 having the composition shown in Table 3 was used.
Five types of gypsum boards were obtained. Furthermore, "Diaproof"
In the above range, and the amount of “white clay SGW-B” to be blended in the gypsum core was changed in the range of 5 to 20 parts by weight with respect to 100 parts by weight of gypsum. Of Examples 46 to 60 were obtained. Each of these gypsum boards had a thickness of 12.5 mm and a specific gravity of 0.70.

From the above 60 types of gypsum board samples,
Six 30 cm square test pieces were collected at 40 ° C.
The sample was dried at a constant temperature to obtain a measurement sample. Then, three sheets were used for measuring the total water absorption for 2 hours and the elongation rate at the time of completely absorbing water for 2 hours, and the remaining three sheets were used for measuring the moisture absorption and release.

The total water absorption for 2 hours was determined according to JIS A 6901.
According to the method of the gypsum gypsum board GB-S, the test piece was immersed in water at 20 ± 3 ° C. for 2 hours and measured. Further, at this time, the dial gauge was fixed with a piece support in the longitudinal direction and the width direction of the test piece, and the elongation ratio when completely absorbing water for 2 hours was measured.

The amount of moisture absorption and desorption was determined by first sealing all the surfaces of the test piece with aluminum tape except for the surface of the test piece so that moisture was absorbed and released only from the surface of the test piece. After leaving it to stand in a thermo-hygrostat at a humidity of 50% for 24 hours, it was left to stand in a thermo-hygrostat at a room temperature of 25 ° C. and a relative humidity of 90% for 24 hours to measure the amount of moisture absorption. Next, the test piece was further subjected to a room temperature of 25 ° C. and a relative humidity of 50%.
Was left standing for 24 hours in a thermo-hygrostat to measure the amount of released moisture. Then, the average value of the three measured values obtained was used as the measurement result, and is shown in Tables 1 to 4.

Comparative Examples 1 to 9 In a normal gypsum board production line, a gypsum core in which neither "Diaproof" nor "Shirasu SGW-B" was blended, only "Diaproof" was used in an amount of 100 parts by weight of gypsum. The composition was changed in the range of 0.5 to 4 parts by weight, and only "Shirasu SGW-B" was mixed in the range of 5 to 20 parts by weight with respect to 100 parts by weight of gypsum. 9 of Comparative Examples 1 to 9 having the composition shown in Table 5
Different types of gypsum board were obtained. These gypsum boards were each 12.5 mm thick, as obtained in the examples.
The board had a specific gravity of 0.70.

From each of the above nine types of gypsum board samples, six 30 cm square test pieces were collected and dried at a constant temperature of 40 ° C. to obtain measurement samples. And 3 pieces 2
For measuring the total water absorption for 2 hours and the elongation for 2 hours
The remaining three sheets were used for measuring the amount of absorbed and released moisture. Then, using the obtained sample, the total water absorption for 2 hours and the elongation ratio and the amount of moisture absorption / release at the time of total water absorption for 2 hours were measured in the same manner as in the examples. The measurement results are summarized in Table 5.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

[Table 4]

[0029]

[Table 5]

As is evident from the results shown in Table 5, in Comparative Examples 2 to 9 in which only one of the water repellency-imparting agent and the inorganic hygroscopic substance was blended into the gypsum core, the amount added It was confirmed that each performance was improved in proportion to. However, Comparative Examples 2 to 6 in which only the water repellency-imparting agent was added
In the case of No. 5, it was found that the moisture absorption / desorption performance was slightly reduced as compared with the case of Comparative Example 1 which was an original gypsum core in which neither the water repellency-imparting agent nor the inorganic moisture absorption / desorption material was blended.
On the other hand, in the case of the gypsum boards of Comparative Examples 7 to 9 to which only the hygroscopic substance was added, it was found that the amount of hygroscopicity increased, but the elongation rate also increased.

On the other hand, Examples 1 to 6 in which both a water repellency-imparting agent and an inorganic moisture absorbing / releasing substance were combined and blended.
In the case of 0, the elongation at the time of water absorption is slightly increased by the incorporation of the moisture-absorbing / desorbing substance as compared with Comparative Examples 1 to 6 in which the substance is not incorporated, but the effect of the combined use of the water-repellent substance appears, and the elongation is further increased. No increase in rate was observed. Further, Example 1
As shown in Tables 1 to 4, in the case of gypsum board of No. 60, improvement of the moisture absorption / release properties was observed depending on the amount of the moisture absorption / release material. Although there is a difference in the moisture absorption / desorption performance depending on the type of the moisture absorption / release material, about 30
A gypsum board having a hygroscopicity of up to 0 g / m ² can be produced.

From the above, in order to add excellent moisture absorption / desorption properties and dimensional stability during moisture absorption to a gypsum board, it is necessary to mix both a water repellency-imparting agent and an inorganic moisture absorption / desorption substance into a gypsum core. Was found to be effective.

[0033]

As described above, according to the present invention,
While maintaining the excellent performance and convenience of gypsum board, and excellent economic efficiency, it has even better moisture absorption and desorption performance,
A high-quality gypsum board having excellent water repellency and good dimensional stability during water absorption can be obtained.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C04B 103: 65 111: 27 (72) Inventor Yuji Ataka 2-1-1 Eboku, Adachi-ku, Tokyo Yoshino Gypsum Stock Shikisha Technology Laboratory

Claims (9)

[Claims] 1. A gypsum board wherein a gypsum core is mixed with a water repellency-imparting agent and an inorganic moisture-absorbing / desorbing substance. 2. A water-repellent agent is added in an amount of 0.05 to 5 parts by weight and an inorganic moisture-absorbing and releasing substance is added in an amount of 3 to 100 parts by weight of gypsum.
The gypsum board according to claim 1, which is blended in an amount of 30 to 30 parts by weight. 3. The gypsum board according to claim 1, wherein the water repellency imparting agent is a silicone-based water repellency imparting agent. 4. The gypsum board according to claim 1, wherein the water repellency imparting agent is a paraffin water repellency imparting agent. 5. The compounding amount of the silicone-based water repellent is:
The gypsum board according to claim 3, wherein the amount is 0.05 to 1 part by weight. 6. The compounding amount of the paraffin-based water repellent is:
The gypsum board according to claim 3, wherein the amount is 0.5 to 5 parts by weight. 7. The inorganic hygroscopic substance according to claim 1, wherein the substance is a clay mineral or one or more substances selected from calcined or acid-treated products. The gypsum board according to claim 1. 8. The gypsum board according to claim 1, wherein the inorganic hygroscopic substance is activated clay. 9. The gypsum board according to claim 1, wherein the inorganic hygroscopic substance is zeolite.